Electric signaling system.



J. D. TAYLOR. ELECTRIC SIGNALING SYSTEM. APPLICATION FILED APR. 28, 1908.

b gm WITNESSES INVENTOR Patented July 19, 1910.

"whereby the block limits may rrnn STATES PATENT OFFICE.

JOHN D. TAYLOR, OE'EDGEWOOD' PARK, PENNSYLVANIA, ASSIGNOR TO' THE UNION SWITCH AND SIGNAL COMPANY, OF OF PENNSYLVANIA.

SWISSVALE, PENNSYLVANIA; A GORPORATION' ELECTRIC SIGNALING SYSTEM.

Specification of Letters Patent. Application filed April 28, 1908. Serial No.

Patented July 19., 1910. 429,587.

To all whom it may concern:

Be it known that I, Join: D. TAYLOR, of Edgewood Park, Allegheny county, Pennsylvania, have invented a new and useful Electric Signaling System, of which the following is a full, clear, and exact description, reference being had to the accompanying drawing, in which the figure is a diagrammatic View illustrating one embodiment of my invention.

My invention has relation to block signal ing systems which are especially adapted for use on railroads in which electric propulsion is employed, and to that class of these signals in which the track rails, instead of being divided into insulated sections or blocks, are electrically continuous for the PIOPlllSlOll current. In systems of this kind which. have heretofore been proposed, the block limits have necessarily been more or less indeterminate, due to the fact that in such systems the relays-which control the signals are operated to set the signals at danger by the short-circuiting action of the trains; and that'the precise points at which this short-circuiting occurs in many cases frequently varies on account of weather and other conditions so that there are no precise limits separating one block from another.

It will. be understood that the term block as used herein does not have its usual signification of an electrically independent section of the traclrrails, but that it is'used' for convenience to designate those portions of thetrack which are located between adjacent signals.

The object of my invention is' to provide means of simple be more defined, and the broadly closely and certainly invention consists in the novel feature of my provision of means whereby the signal-controlling relaysare operated by means of currents inducted by the signaling currents. Inasmuch as the portions of the track where,

these induced relay operating currents are generated can be closely limited, means are thus provided for ositively controlling the operation of the re ays and for determining the block limits.

The precisenatu-reof my invention will be best understood by reference tothe accompanying diagram, in which I have shown one embodiment thereof, and which w1ll now be described, it being premised, howand effective character ever, that various changes may be made therein by those skilled in the art without departing from the spirit and scope of my invention as defined in the appended claims rail or trolley wire IL, and the other terminal is connected with conductor m, which connects the two rails of the track.

B is an alternating. current generator for supplying the signaling current, and should be adapted to give a current of considerably higher frequency than the generator A where the latter is an alternator. The current from the generator B is led to the various signalmg instruments by means ofthe line .wires a r C, C, are transformers, whose primary coils p, 7), are connected across the line wires 7, 7c, and whose secondary coils s, s, are connected to the track rails 1', r at points which are as nearly as may be at the middle of the respective blockswhich the transformers supply with current- The rails 1-, r are electrically continuous for the propulsion current.

Opposite points of the 'two rails marking approximately the ends of the res ective blocks are joined by transverse con uct-ors m, m, me, etc., these cross connections .forming closed circuits for the currents induced in the secondary coils of the transformer,- that is, the current from any secondary coil will flow through the rail 1 to theadjacent cross conductors to the rail r, and back to the transformer. These crossconnections further serve to balance the propulsion current flowing in the track rails. The currents flowing in those closed circuits will produce a magnetic flux around each rail; and if a loop of wire or other conductor, of which the cross-conductor may form a part, is so placed as to be included within the lines of force of this flux, the conductor will have induced in it'an electromotiveforce which may be utilized to produce a current for operating the signal-controlling rela R,-R, R", R" etc., designate these signal control-lingrelays. In the arrangement shown they consist each of two elements, the field elements f, f, etc., being connected 'to shunt the current which causes t e magthe adjacent cross-conductor m, thence backto the other terminal of the armature a. The circuit of the armature a is formedin a similar manner by the other loop g of the conductor, each pair of adjacent relays be ing on opposite sides of one of the crossconductors, and utilizing such cross-conductor as a common part of their circuits.

Two relays are provided for each block section, said relays having the contacts of the local signal circuit which they control in series with each other.

S, S', designate signals for uarding the respective blocks, these signaIs being arranged to go to danger in the usual manner upon the opening of their controlling circuits.

'1 is a conventional representation of a train, which is shown as between the signals S, S and between the relay It and its transformer- O. As will be seen, this train shunts the current from the transformer secondary from those portions of the track rails to which the loop g is adjacent. There will therefore be no flux through this coil and no current induced in it so long'as the train occupies this portion of the block. The relay governed by said loop will therefore open its contacts and cause the signal to go to danger position. \Vhen the train passes the conductor m, it will begin to cut out the flux passing through the loop formed by the wire g and will, when it arrives at some point between m and 9, cut

out suhicient or this flux so that there will not be enough remaining to provide sutlicient currenttoenergize the armature a of the relay 1*. vWheIfthis occurs, the circuit of the signal S will be opened and this signal will assume the danger position. It will, therefore, be seen that when a train occupies any portion of any block, one of the relays of that block will have its armature deiinergized so that the signal protecting the train will be held atda'ngcr'; and that as the train enters the next succeeding block it will at once gain controhof the signal guarding that block before it loses control of the signal in rear. In this manner, the train is at all times protected by a danger signal in the rear. Inasmuch as the loops 9, g, etc can be confined to those portions of the track rails adjacent to the block limit, and as the corresponding relays will be short-circuited only at such times as the train is in osition netic flux which induces the" relay operating currents into these loops, the points at which the relays will be short-circuited can be very closely determined, and thus give a very definite point at which the signals should be set to danger.

Owing to the fact that the alternator B produces a current or higher frequency than the generator A, where that generator supplies alternating current, it will be seen that the relays can be so constructed as not to be affected by the propulsion current. It will also be seen that there can be no interference in the operation of difierent relays, since each relay is operated to clear the corresponding signal only by the current induced in its own induction loop.

It will be obvious that various changes may be made in my invention without departing from its essential features. Thus, various forms of relays may be employed; their field elements may be connected in the induction loops, and their armature elements across the line conductors j, is, and various other changes may be made.

I claim 1. In a block signaling system, rails which are electrically continuous for both propulsion and signaling current, conductors connecting said rails at points adjacent to the block limits, signal controlling relays, and conductors arranged in inductive relation to the track rails for operating'said relays,

said conductors being connected to the relays through the cross-connections between the. track rails; substantlally as described.

2. In combination with an electric railway the rails' of which are electrically continuous for both propulsion and signaling currents, a plurality of block sections formed by crossconnecting conductors between the rails, sig nal controlling relays, and conductors arranged in inductive relation with the track rails, said conductors being connected to the relays through the cross-connections between the track rails. v

. 3'. In' combination with a railway, both rails of which are electrically continuous, a plurality of block sections formed by crossconnecting conductors between the two lines of rails at points adjacent the desired block section limits, signal controlling relaysyuonductors for each block section arranged in close inductive relation with the track rails, and a controlling circuit for each relay including said conductors and a cross-connecting conductor.

.. In testlmony whereof I have signed'imy' name to this specification in the presence of two subscribed witnesses.

JOHN D. TAYLOR. Witnesses:

S. O. MENDENEALL, JAMES CHALMEns, Jr. 

